Appearance
We email you a link and a six-digit code. Either one signs you in; there is no password.Enter your email. We send a link and a six-digit code to confirm it — no password to remember. The account is free.
By continuing you accept the Terms and the Privacy policy.
Your account
Free accountLifetime access
Data science & machine learning reference
Every concept explained from the book or paper it comes from, with a figure and a worked example that was actually run.
TryGradient descentLinear regressionBayes' theoremPerceptron
18 pages free in full. The rest unlocks once for $20, with no subscription.
Free account · 18 free · 108 lockedUnlock
Lifetime access · every page is open to youBrowse all concepts
A locked page is never a dead end. The definition, the formula and the intuition are open to everyone; the rest of the page opens with access.
Open to everyone
With access
The locked text is never sent to your browser: not in the page, not in search, not in the feed.
Pick the one that matches why you are here. All four work on the free pages.
Every page opens with a one-sentence definition and a formula — never behind a lock.
Search conceptsTracks in prerequisite order, a quiz per page and progress that remembers where you stopped.
See the tracksDense pages, catalogues that put methods side by side, a glossary and the ⌘K palette.
Open the cataloguesEverything unlocked, quizzes graded and saved, your place kept across your devices.
See what is includedGradient descent
Dive into Deep LearningZhang, Lipton, Li, Smola
§12.4.1§12.5§12.3.1.1
Deep LearningGoodfellow, Bengio, Courville · 2016
§8.2.2§4.3.1
Every claim points to the chapter or section of the book or paper that says it. The full list is public.
Audit the sourcesEach page has a figure that makes a point you can check — not a decoration.
See an example page$ python gradient_descent.pyeta=0.1 w= 2.7938 loss=0.0425eta=0.5 w= 3.0000 loss=0eta=0.9 w= 2.7938 loss=0.0425eta=1.05 w= -6.4153 loss=88.65Worked examples are real scripts, and the output shown is what they printed. When a result disagreed with the textbook, the page says so.
How it is madeEvery page ends with three questions. Each answer is explained, with the section it tests and the source behind it.
Free sample Gradient descent
3 questions
Each answer is explained, with the section it tests and its source.
After each answer
Twenty questions drawn at random from every page on the site, one question per page so no corner of the site dominates. Nothing is shown until you finish; then every answer is explained. It comes with lifetime access.
Take the final test Unlock the final testFoundations first, applications last. Every topic has free pages you can read in full.
A track is an ordered path through the pages, each with its quiz. With lifetime access, its ring fills as you read them.
From a train/test split to transformers, in the order each page needs.
Distributions, inference, and the mistakes that sink analyses.
Linear models, trees, ensembles, clustering — how each one fails.
Networks, optimisation, regularisation and what to do when training fails.
Tracks are being built; these four start from pages that already exist.
A few pages in every topic are free. One payment unlocks everything else — every page, every quiz, your progress on all your devices — and nothing renews.
Free
$0
No account needed
Lifetime
$20 one time
Pay once, keep access
Paid once. No renewal and no charge to come.
Prices are in US dollars. Any VAT or tax that applies where you live is added at checkout. You can read the Terms and the Refund policy before you pay. Terms · Refunds
| Free | Lifetime | |
|---|---|---|
| Free pages, in full | Included | Included |
| Definition, formula and intuition of every page | Included | Included |
| Quizzes on the free pages | Included | Included |
| Every cheat sheet; the PDF with a free account | Included | Included |
| All pages and catalogues | Not included | Included |
| The quiz on every page, and a final test drawn from all of them, saved to your account | Not included | Included |
| Progress and tracks in your account, on all your devices | Not included | Included |
| New pages and practice as they land | Not included | Included |
What you have read, how your quizzes went, and where to pick up — recorded as you read.
Families of methods, compared side by side.
Pages added or revised lately, newest first.
A few pages in every topic, read in full with no account. On every other page the definition, formula, intuition and sources are open too.
Every page, catalogue and quiz on the site, now and as it grows, with no renewal. Your progress and quiz results are kept in your account and follow you to every device.
Not to read the free pages. You need one to buy, and lifetime access keeps your progress and quiz results in your account, on every device. You sign in with a link or a code from an email; there is no password.
It is not sent to your browser at all, so there is nothing to find in the page source, the search index or the feed.
The Terms and the Refund policy are shown before you pay. It is one payment, not a subscription, so nothing renews and there is nothing to cancel.
No ads and no tracking cookies. Visits are counted anonymously with Umami: no cookie, nothing that could tell who you are, and nothing at all from a browser that asks sites not to track it. Signing in sets the cookies that keep you signed in: the session itself; one that remembers whether your account is free or has access, so pages draw right; and, for the hour it takes to finish signing in, one holding the address the code went to. The cookies page lists them.
The free pages are free in full, with no account. If they are what you were looking for, one payment unlocks the rest.
Paid once. No renewal and no charge to come.
The message could not be sent. Please write to us directly: support@artofds.com